1. Field of the Invention
The present invention relates to surgical instruments known as trocars which are used in endoscopic surgery to pierce or puncture an anatomical cavity of a patient to provide communication with the cavity during a surgical procedure. More particularly, the present invention relates to an improved non-cutting piercing tip of an obturator assembly of a trocar.
2. Description of the Prior Art
Endoscopic surgery is a significant method of performing surgical operations and has become the surgical procedure of choice due to its patient care advantages over xe2x80x9copen surgery.xe2x80x9d A particular type of endoscopic surgery is laparoscopic surgery. A significant advantage of laparoscopic surgery over open surgery is the decreased post-operative recovery time. In most instances, a patient is able to leave the hospital within hours after laparoscopic surgery has been performed, whereas with open surgery, a patient requires several days of hospital care to recover. Additionally, laparoscopic surgery achieves decreased incidents of post-operative abdominal adhesions, decreased post-operative pain, and enhanced cosmetic results.
Conventionally, a laparoscopic surgical procedure begins with the insufflation of the abdominal cavity with carbon dioxide. The introduction of this gas into the abdominal cavity lifts the abdominal wall away from the internal viscera. The abdominal wall is then pierced or penetrated with a device known as a trocar. A trocar includes a housing assembly, a cannula assembly attached to the housing assembly to form a bore through the trocar, and a piercing element called an obturator. The obturator slides through an access port formed on the upper end of the housing assembly and through the bore of the trocar. After insertion of the trocar through the abdominal wall of the patient, the obturator is removed by the surgeon while leaving the cannula protruding through the abdominal wall. Laparoscopic instruments can then be inserted through the cannula to view internal organs and to perform surgical procedures.
Traditionally, the piercing tip of the obturator of a trocar has employed a sharp cutting blade to assist the surgeon in penetrating the abdominal wall. However, certain trocars, for example, as disclosed in U.S. Pat. No. 5,817,061 to Goodwin, have employed a pair of blunt-edged blades or tissue separators which are located on the tip of the trocar to facilitate the penetration or dissection of tissue.
Both of the trocar assemblies disclosed in U.S. Pat. No. 5,817,061 to Goodwin and U.S. Pat. No. 5,591,192 to Privitera are manufactured and sold by Ethicon Endo-Surgery, Inc. Trocars as described in the ""061 and ""192 patents have at the time of filing this application been recalled by Ethicon since the tip of the obturator has been prone to failure. In particular, the tip of the trocars disclosed in the ""061 and ""192 patents have experienced incidents of snapping off during the insertion of the trocar. It is believed that this failure may be attributable to the blunt shape of the tip and the forces to which the tip is subjected upon insertion.
Accordingly, it would be desirable to have an obturator of a trocar with a blunt piercing tip that is structurally capable of resisting increased insertion forces associated with blunt tipped obturators without failing. This novel and useful result has been achieved by the present invention.
In accordance with the present invention, a trocar is provided which comprises a metal housing assembly and a cannula assembly attached to the housing assembly to define an axial bore therethrough.
A trocar in accordance with the present invention may further comprise an obturator assembly which slidably engages the axial bore defined by the cannula assembly. The obturator assembly comprises a shaft having a piercing end for insertion into a patient and a handling end for gripping by a surgeon. The piercing end of the shaft of the obturator includes a piercing tip having an upper face and a lower face which taper from the shaft to form a non-conical, blunt head. Additionally, wing elements having lateral edges are located on opposite sides of the piercing tip between the upper face and lower face.
In a preferred embodiment of the present invention, the piercing tip of the obturator is removably attached to the shaft of the obturator. Therefore, the obturator may be used with piercing tips of various configurations-such as blunt tips to separate tissue and sharp tips for cutting tissue.
In accordance with the present invention, penetration forces associated with insertion of a blunt tip trocar into a wound track of a patient are reduced due to the improved wing elements. The lateral edges of each wing element widen the wound track to ease insertion of the trocar into the patient. As a result, a trocar in accordance with the present invention is better able to resist these penetration forces without failure as compared to existing blunt tip trocars.